Method and apparatus for trimming containers

ABSTRACT

Method and apparatus for trimming a container having an open end wherein the container is held during the trimming operation, including a multi-station assembly for holding the container to be trimmed stationary during trimming, ejecting the trimmed portion and ejecting the trimmed container.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Division of application Ser. No. 10/671,394, filedSep. 25, 2003.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for trimmingcontainers, particularly blow molded containers, in a multi-stationoperation, preferably at a high speed.

In certain applications it is desirable to provide trimming of theformed container to remove a scrap piece. This is particularly true inblow molding applications. Most often, this has been done on extrudedblow molded containers to remove blow heads and to provide dispensingopenings that usually have a thread or other retainer for securing aclosure cap thereon. Such trimmings are disclosed, for example, by U.S.Pat. No. 5,167,968 to Dunlap et al. and U.S. Pat. No. 6,367,360 toDunlap et al., both of which are assigned to the assignee of the presentapplication.

It would be highly desirable to provide a high speed trimming method andapparatus that is convenient and expeditious to employ, and it is aprincipal objective of the present invention to provide such a methodand apparatus.

Further objects and advantages of the present invention will appearhereinbelow.

SUMMARY OF THE INVENTION

In accordance with the present invention a method and apparatus isprovided for trimming a plastic container having an open end, whereinthe container is held stationary during the trimming operation.

In accordance with the method of the present invention a multi-stationassembly is provided having spaced stations which hold the container tobe trimmed during the trimming operation. The method includes: movingthe container to be trimmed onto the multi-station assembly at a firstoperating stage; moving a knife into engagement with the container to betrimmed at a second operating stage; trimming said container at a thirdoperating stage by said knife, with the container held stationary duringtrimming; ejecting the trimmed portion at a fourth operating stage; andejecting the trimmed container at a fifth operating stage; wherein saidcontainer traverses stations of said multi-station assembly for saidstages. Separate stages should be performed in the area of separatestations, but a stage may occupy more than one station in themulti-station assembly. For example, the trimming operation desirablyoccupies several stations.

The present invention also includes an apparatus for trimming a plasticcontainer having an open end. In accordance with the apparatus of thepresent invention a multi-station assembly is provided having spacedstations which hold a container during trimming, including inlet meansto move the container to be trimmed onto said assembly at a firstoperating stage, a knife operative to trim said container, means to movethe knife into engagement with the container to be trimmed at a secondoperating stage, means to move said knife around said container to betrimmed to trim said container at a third operating stage; means to holdthe container stationary during trimming, means to eject the trimmedportion at a fourth operating stage, and means to eject the trimmedcontainer at a fifth operating stage, wherein said container traversesstations of said multi-station assembly for said stages.

The present invention also includes an intermediate plastic containerfor trimming into a final, trimmed container.

Further features of the present invention will appear hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more readily understandable from theillustrative, accompanying drawings, wherein:

FIG. 1 is a partially schematic view illustrating the multi-stationassembly of the present invention;

FIG. 2 is a detail view of a container to be trimmed moved into themulti-station assembly;

FIG. 3 is a detail view of a container being lifted into a neck holder;

FIG. 4 is a further detail view of a container being lifted into a neckholder;

FIG. 5 is an enlarged, detail view of a container on a pedestal beinglifted into a neck holder;

FIG. 6 is an enlarged, detail view similar to FIG. 5 of a containerraised into the neck holder;

FIG. 7 is an enlarged, detail view of a container raised into the neckholder with the knife in trimming position;

FIG. 8 is an enlarged view of portion 8 from FIG. 7 showing the knifeengagement with the container;

FIG. 9 is an enlarged, detail view of the trimmed container separatedfrom the trimmed portion;

FIG. 10 is an enlarged, detail view showing the trimmed portion beingejected; and

FIG. 11 is a side view of an intermediate plastic container with athreaded finish portion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the preferred embodiment of the present invention a blow moldedplastic container is provided for trimming in accordance with thepresent invention. The container is preferably of the type made from aninjection molded preform having an open end with a portion adjacent theopen end which requires trimming. The container may be round ornon-round and is desirably held in a stationary position generallyadjacent the portion requiring trimming during the trimming operation.The neck finish portion of the final container may be a threaded orsnap-on finish, and any plastic material can be used, preferablypolyethylene terephthalate. Advantageously, the process and apparatus ofthe present invention is capable of high speed operation, for example,in accordance with the present invention one may achieve a trimming rateof at least 5,000 containers per hour and may trim non-round containersat a rate of about 10,000 bottles per hour and round containers at arate of about 15,000 bottles per hour.

FIG. 1 shows an exemplificative multi-station assembly 20 of the presentinvention including twelve spaced operating stations 20-1 through 20-12,with a first inlet station 20-1 and a final station 20-12. Naturally,the number of stations may vary.

The container to be trimmed 26 enters the multi-station assembly atinlet station 20-1, as by inlet wheel 22 which may hold severalcontainers and deposits same sequentially at the inlet station. Thecompleted, trimmed container is ejected at outlet station 20-11 as ontooutlet wheel 24. Final station 20-12 is located between the inlet andoutlet stations and provides an in-between station for examination ofcomponents. The remaining operations are conducted at the remainingstations and will be described below.

FIG. 2 shows a detail view of a container to be trimmed 26 moved intostation 20-1 of multi-station assembly 20 at a first stage of theoperation. The container 26 is held on a pedestal 28 by waist band 30with neck holder 32 in position above the container. Knife 34, knifeactuating arm 36 and trimmer head 38 are also positioned above container26. Between the first station 20-1 and the second station 20-2 pedestal28 raises and lifts container 26 into trimming position at the secondstation as shown in FIG. 3, and from the second station 20-2 to thethird station 20-3 knife actuating arm 36 moves knife 34 into trimmingposition at a second stage of the operation and into engagement with thecontainer while neck holder 32 firmly engages and holds container 26beneath the area to be trimmed at the third station, as also shown inFIG. 3.

FIGS. 4–5 are further detail views of container 26 being lifted bypedestal 28, and FIG. 6 is a further detail view of the container 26raised into the neck holder 32. FIG. 7 is an enlarged view of thecontainer 26 raised by pedestal 28 into neck holder 32 with the neckholder firmly holding the container beneath the area to be trimmed 56and with knife 34 engaged with the container in trimming position in thesecond stage. FIG. 8 is an enlarged view of portion 8 from FIG. 7showing knife 34 in engagement with container 26 for trimming. FIG. 8clearly shows the portion of container 26 to be trimmed 50 and theportion remaining after trimming which is the trimmed container 52. FIG.7 also clearly shows rotary cam 40, cutter components mounting plate 42,roller 44 for moving knife 34, spring tensioner 46, roller mount stop 48and knife actuating arm 36, all for camming, positioning and movingknife 34 in the trimming operation, wherein the knife is moved aroundthe container to trim the container at the area to be trimmed 56. Knifeactuating arm 36 is moved downward and cam 40 engages knife 34 withcontainer 26. The trimming operation takes place in the third stage ofoperation and desirably occurs over several stations. For example, inthe preferred embodiment the trimming operation starts at the station20-3 and continues to the station 20-8. The container is desirably heldstationary on pedestal 28 by neck holder 32 during the trimmingoperation while knife 34 is rotated around container 26 during thetrimming operation by cam 40, roller 44 and knife actuating arm 36.

As clearly shown in FIG. 8, for example, the outer diameter 58 of theportion to be trimmed 50 is no greater than and is desirably smallerthan the outer diameter 60 of the finish portion 62 of the trimmedcontainer 52, which in this embodiment is a snap-on finish, although ascrew-threaded finish may also be used. The desirably smaller outerdiameter of the portion to be trimmed is advantageous as less plasticmaterial can be used in the portion to be trimmed 50, which may be athrow-away component. Also, this enables one to better control thethickness at the top of the trimmed container 52 and finish portion 62.This also facilitates controlled material distribution in the finisharea to enable an even distribution of wall thickness in the finish areato enhance finish effectiveness and trimming effectiveness, especiallyin a non-round container. In addition, the desirably smaller outerdiameter 58 of the portion to be trimmed 50 facilitates making thefinish area thicker in the final, trimmed container. It also facilitatesblow out in the blow molding procedure for snap beads in a snap onfinish or threaded areas for a threaded finish.

Between stations 20-8 and 20-9 the trimming operation has stopped andthe knife 34 and knife actuating arm 36 are raised and trimmed portion50 separated from trimmed container 52. The trimmed portion 50 is movedaway from trimmed container 52 by arm 54 while the trimmed container 52is held on pedestal 28 by neck holder 32 as shown in FIG. 9. This takesplace between stations 20-8 and 20-9. The trimmed portion 50 is removed,as by air blowing, as for example at station 20-9 at the fourth stage ofthe operation as shown in FIG. 10.

Between the stations 20-9 and 20-10 the pedestal 28 drops down tostarting position and at station 20-11 the trimmed container 52 isremoved as shown in FIG. 1 as on outlet wheel 24 at the fifth stage ofthe operation.

FIG. 11 shows an alternate embodiment of intermediate container to betrimmed 126, with upper portion to be trimmed 150, lower portionremaining after trimming 152, and intermediate finish portion 162 whichin this embodiment is a threaded finish. Here again, the outer diameterof the upper portion is no greater than the outer diameter of the finishportion.

Thus the process and apparatus of the present invention simply andexpeditiously obtain a high speed operation and is usable for round andnon-round containers. The same number of stations can be used for bothround and non-round containers, and the exact number of stations is notcritical. The knife rotates at a controlled speed while the container tobe trimmed, round or non-round alike, is held stationary. This avoidsbottle movement and allows for a highly accurate trimming operationcapable of trimming at least 5,000 containers per hour. Mechanical airvalues are preferably used to move the knife down and into engagementwith the container to be trimmed.

The container to be trimmed of the present invention, with the finisharea at an intermediate portion on the container, enables one to providea heat set finish area in the final, trimmed container, wherein thefinish area in the final, trimmed container can advantageously resisthot filling. The even distribution of plastic in the finish area on anon-round container is particularly suitable for a heat set finish.

Stationary trimming, when the container is stationary during thetrimming operation, facilitates trimming containers with slightirregularities on round, non-round and offset container openings, and onboth round or non-round containers with screw thread or snap on finishareas. This enables one to readily provide exotic opening shapes, as forexample, triangular openings, offset oval openings, tear shapedopenings, or figure eight shaped openings. Further, trimming of round ornon-round containers in accordance with the present invention as well asoffset neck areas allows packaging efficiencies, for example, square orrectangular packages can be readily obtained as well as packages withoffset round openings.

It is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modification of form, size, arrangement of parts anddetails of operation. The invention rather is intended to encompass allsuch modifications which are within its spirit and scope as defined bythe claims.

1. An apparatus for trimming a plastic container having an open end anda base, which comprises: a multi-station assembly for holding acontainer during trimming wherein said assembly includes a plurality ofspaced stations and wherein said container traverses stations of saidmulti-station assembly for operating stages, including means to supportthe base of the container during its traverse through the multi-stationassembly; inlet means to move the container to be trimmed onto saidmulti-station assembly at a first operating stage; a knife operative totrim said container; means to move said knife into engagement with saidcontainer to be trimmed at a second operating stage; means to move saidknife around said container to be trimmed to trim said container at athird operating stage including a roller and tapered cam for camming,positioning and moving the knife; means to hold the container stationaryduring trimming including a holder which holds the container beneath thearea to be trimmed during trimming; means to the eject the trimmedportion at a fourth operating stage; and means to eject the trimmedcontainer at a fifth operating stage.
 2. An apparatus according to claim1, including a plurality of stations for said trimming.
 3. An apparatusaccording to claim 1, wherein said apparatus is a high speed apparatusfor trimming at least 5,000 containers per hour.
 4. An apparatusaccording to claim 3, wherein said apparatus is operative to trim atleast 10,000 containers per hour.
 5. An apparatus according to claim 1,including a pedestal to hold the container during its traverse throughthe multi-station assembly.
 6. An apparatus according to claim 1,wherein separate stages are performed in the area of separate stations.7. An apparatus according to claim 1, wherein the upper portion of thetrimmed container has a finish portion, and providing that the outerdiameter of the trimmed portion is no greater than the outer diameter ofthe finish portion.
 8. An apparatus according to claim 1, including aninlet wheel for holding a plurality of containers to be trimmed and forsequentially feeding the containers onto said multi-station assembly. 9.An apparatus according to claim 8, including an outlet wheel, whereinthe trimmed containers are ejected onto said outlet wheel.
 10. Anapparatus according to claim 5, wherein said pedestal is operative toraise the container into the holder.
 11. An apparatus according to claim10, wherein said pedestal is operative to lift the container intotrimming position by raising the pedestal.
 12. An apparatus according toclaim 1, including a knife actuating arm for moving the knife intotrimming position while the container is held stationary by said holder.13. An apparatus according to claim 12, wherein the knife actuating armmoves downward and the knife is engaged with the container by camming.14. An apparatus according to claim 1, including means for separatingthe trimmed portion from the trimmed container after the trimmingoperation and before ejecting the trimmed portion.
 15. An apparatusaccording to claim 5, wherein the pedestal is operative to be lowered toa starting position after the trimming operation.
 16. An apparatusaccording to claim 1, wherein the knife is held on a mounting plate andspring tensioner connected to the roller, wherein the spring tensioneris spaced from the axis of the tapered cam.